ᐅ Correct Installation of Beams and Support Columns

Good morning, dear community. I have purchased an existing property and now want to remove a wall. The structural engineer has already been on site and completed the calculations for selecting the beams.

A HEA 100 is being used as the support beam and an HEB 140 as the ceiling beam. The wall has already been removed and temporarily supported down to the basement with several masonry braces.

Is it correct that I should first concrete the base of the support beam and the ceiling beam into the masonry (mortar bed)? Of course, the beams will be welded together beforehand. Once these two bearing points have hardened, I would use grout from the company QuickMix to seal the mortar joint. Would this then ensure the load transfer to the ceiling beam?

Or do I need to apply mortar onto the ceiling beam, press it up against the ceiling with masonry braces, and then shore up the support beam with wedges?

I would appreciate any tips and suggestions.

Best regards

here is the picture as an overview