https://youtu.be/E_In02xzpyE
https://www.germanautosolutions.com/..._tools_diy.php
You need some timing tools to hold the cams at TDC and other set to exactly position the reluctor wheel aka "impulse sending wheel".
I wouldn't want to attempt guesswork timing. You don't need GAS brand timing tools. The cam lock tools are very simple I'd bet somebody sells on eBay cheap. The GAS solution for the timing wheel is a better design than BMW's and I highly recommend it. You can use for 1-4 or 5-8 you only technically need one.
Learn from my mistake don't try to do the 720° turn with the timing plate nut loose and the timing pin installed. The nut self tightens!