Hi Yan, the titleblock (frame) you attached is drawn the correct size but is in a drawing that was based in milliemeters.
I cleaned up the titleblock, changed your Mtext into attributes and then made it into a block called Titleblock.
I inserted this into the paperspace of your Iso-model at 1:1. I then created a Page setup (just as we did together the other day).
Next I created a viewport on a layer designated for viewports and set to non-plot.
Then I set the scale inside the viewport at 1:2.

To construct the geometry, I suggest you create a plan view and then a side view.
You can calculate where the angles are between the views based upon the dimensions given in the exercise. You can then label all the dimensions in plan view if that helps you know how to draw it in isometric view.
I would not worry about the holes and fillets until the end of drawing the geometry. (I just added a sample plan and side view to the attached dwg).
Be careful too, as I notice you draw lines on top lines and lots of short line segments which can make things messy.
John Vellek
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