Thank you both!

Each tool loads in a way that its author considers appropriate to its use. The tools' installation and activation/use are clearly explained on its download page... Each tool that has an RB file in the Plugins folder will 'auto-load' when SketchUp starts, Some tools are made as 'Extensions' - these need activating from the Preferences > Extensions list, after they are first installed. This is appropriate for more complex tools - you can switch then on/off this way, although the Extension that's 'off' only becomes unavailable after SketchUp is restarted. Some tools have a Toolbar - activated from its View > Toolbars entry. Clicking on the buttons runs various aspects of a tool's operation. Many tools have entries in one of the standard SketchUp menus, or submenus within them. These items allow you to set a shortcut-key to them - in the same way that you can with the native-tools. Many 'tools' will appear in the Plugins menu. However, some are regarded as 'Tools' or 'Draw' items and can appear there. Also some are to do with File, View/Camera etc... Some tools are accessible from the right-click context-menu. Usually these are only displayed or not-disabled [grayed-out] when specific conditions are met - for example a tool that only works when 'one group' is selected might only display when you have 'one group' selected. Some very specialized tools don't even appear in any menu or toolbar - these are activated by typing commands into the Ruby Console - they are for a one-off use in unusual circumstances when a menu item would be rarely used... So... read the tool's usage notes and use them as indicated...

Layout is an extension of sketchup that allows you to arrange production sheets with views of your model. As for drafting in sketchup, you can set your view to orthographic in Camera>Parallel Projection. You can activate the toolbar Views for iso, top, left, right, front in View>Toolbars>Views. Click on this and a toolbar with little house icons will pop up. Does this help?

@brookefox said: The OP may not care, but I do. haha (nice job btw)

I cannot see much understandable text in metric version. So cannot try to edit it. It shows sanskrit language perhaps.

Layers do NOT separate geometry [unlike in CAD], all that SUp layers do is control objects' visibility. All of you 'raw' geometry should be made on Layer0. By making/moving geometry inside groups or component-instances you separate the geometry from other geometry that might otherwise stick to it. You then control visibility of the groups/instances using layers of those. You cannot separate some geometry by simply moving it onto an invisible layer as any new geometry you add within the same context will still merge with it. You are best advised to always have LAyer0 set as your current-layer. For example draw a rectangular face on the current-layer [Layer0]. Select the face [not its edges] and change it to be on another layer [say Layer1] that's switched off. You can no longer see it. Now erase one of the rectangle's edges. Switch the Layer1 and the face has gone too, that's because although you had [inadvisably] moved the face onto a hidden layer it was still connected to its edges on Layer0 and therefore was erased when an edge went. No try this... Draw another rectangular face on the current-layer [Layer0]. Select the face and Group it. Draw another rectangular face on the current-layer [Layer0] exactly over the group. Erase the face but leave the edges. Now select the group and move it onto Layer1 and switch that layer off. You are left with the unfaced edges. Erase and edge. Switch Layer1 back on and the face reappears. This is because you have separated some of you geometry using groups and changed visibility of the group's layer. So if you want to trace over something make sure you are working over a group/instance and then only the geometry in the current working context will interact