Do you want render tree for user, etc. for choose some node?
$tree->render();
Don´t forget link css styles
<link rel="stylesheet" href="css/helbrary-tree.css">
Set active node
$renderer = $tree->getRenderer();
$renderer->setActiveNode(5);
Customize choose button
$renderer = $tree->getRenderer();
$renderer->setActionItemTemplate('pathToMyTemplate.latte');
// default action item template - chooser.latte
<a class="helbrary-tree-chooser" data-key="{$node->getKey()}">
Choose
</a>
Do you want set key of choose node to some input?
<input type="text" id="my-input">
$renderer = $tree->getRenderer();
$renderer->setTargetInputForChooseNode('my-input');
// now when I choose some node will be set value of input my-input to key of choose node