How to use the cx/ui.FocusManager.focusFirst function in cx

case code("J"):
                    if (e.currentTarget.nextSibling)
                        FocusManager.focusFirst(e.currentTarget.nextSibling);
                    break;

                case KeyCode.left:
                case code("H"):
                    list = closest(e.target, el => el.classList.contains("cxb-tasklist"));
                    if (list.previousSibling) FocusManager.focusFirst(list.previousSibling);
                    break;

                case KeyCode.right:
                case code("L"):
                    list = closest(e.target, el => el.classList.contains("cxb-tasklist"));
                    if (list.nextSibling) FocusManager.focusFirst(list.nextSibling);
                    break;
            }
        },

let u1 = registerKeyboardShortcut({ keyCode: 27 }, (e) => {
        if (document.activeElement.classList.contains("cxb-task"))
            return;
        e.preventDefault();
        e.stopPropagation();
        let els = document.getElementsByClassName("cxb-task");
        if (els && els.length > 0) FocusManager.focusFirst(els[0]);
    });

}, () => {
                        if (elementReceivingFocus)
                            FocusManager.focusFirst(elementReceivingFocus);
                    });

break;

                case KeyCode.left:
                case code("H"):
                case code("B"):
                    list = closest(e.target, el => el.classList.contains("cxb-tasklist"));
                    if (list.previousSibling && list.previousSibling.previousSibling)
                        FocusManager.focusFirst(list.previousSibling.previousSibling);
                    break;

                case KeyCode.right:
                case code("W"):
                case code("L"):
                    list = closest(e.target, el => el.classList.contains("cxb-tasklist"));
                    if (list.nextSibling && list.nextSibling.nextSibling)
                        FocusManager.focusFirst(list.nextSibling.nextSibling);
                    break;
            }
        },

let u2 = registerKeyboardShortcut({ keyCode: 191 }, (e) => {
        if (e.target.tagName === "INPUT" || e.target.tagName === "TEXTAREA")
            return;
        e.preventDefault();
        e.stopPropagation();
        if (!e.shiftKey) {
            let searchEl = document.getElementById("search");
            FocusManager.focusFirst(searchEl);
        }
        else {
            History.pushState({}, null, "~/help");
        }
    });

switch (e.keyCode) {
                case code("K"):
                    if (e.currentTarget.previousSibling)
                        FocusManager.focusFirst(e.currentTarget.previousSibling);
                    break;

                case code("J"):
                    if (e.currentTarget.nextSibling)
                        FocusManager.focusFirst(e.currentTarget.nextSibling);
                    break;

                case KeyCode.left:
                case code("H"):
                    list = closest(e.target, el => el.classList.contains("cxb-tasklist"));
                    if (list.previousSibling) FocusManager.focusFirst(list.previousSibling);
                    break;

                case KeyCode.right:
                case code("L"):
                    list = closest(e.target, el => el.classList.contains("cxb-tasklist"));
                    if (list.nextSibling) FocusManager.focusFirst(list.nextSibling);
                    break;
            }
        },

onTaskListKeyDown(e, instance) {
            let code = c => c.charCodeAt(0),
                list;

            switch (e.keyCode) {
                case code("K"):
                    if (e.currentTarget.previousSibling && e.currentTarget.previousSibling.previousSibling)
                        FocusManager.focusFirst(e.currentTarget.previousSibling.previousSibling);
                    break;

                case code("J"):
                    if (e.currentTarget.nextSibling && e.currentTarget.nextSibling.nextSibling)
                        FocusManager.focusFirst(e.currentTarget.nextSibling.nextSibling);
                    break;

                case KeyCode.left:
                case code("H"):
                case code("B"):
                    list = closest(e.target, el => el.classList.contains("cxb-tasklist"));
                    if (list.previousSibling && list.previousSibling.previousSibling)
                        FocusManager.focusFirst(list.previousSibling.previousSibling);
                    break;

                case KeyCode.right: