You say you have a mast. Do you have a mast extension?

The normal kit includes:
1) sail
2) mast of length and stiffness to suit sail
3) extension to fine tune mast length and to suit mast diameter (standard or reduced diameter)
4) mast foot to suit extension (euro pin or pinch pin) that has a bolt for fixing in the mast track with a T nut.

You can drill a hole in the front of your MB and fix your mast foot to that.
You rig your sail mast and extension as a unit and clip it to the mast foot.

PVC conduit will be too flexy for a boom.
A cheap second hand ally boom would be ideal.

good luck.

Here's a classic old rig, complete... which would be very cheap...