A/C compressor and condenser replacement

If you are replacing those you should also flush the system, put a vacuum on it to be sure it holds then add in a full charge of oil. If you are using a new compressor be sure to drain it before you install it. Then just add enough oil to what you drained to make the full charge amount.
If you do not pull a vacuum on the system you will end up with air and moisture in there with the oil and R134A. The air will cause problems and the moisture will cause acid formation. Both are bad things.

If you have only front AC you need 8 oz of PAG oil. If you have front and rear AC you need 11oz.

For the R134A - Front AC only - 1.8 pounds.
Front and rear AC - 3.0 pounds.

Take a look at this guide. It should answer some of your questions.
https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

However, if your compressor is making noise you will need to flush the system as well. For that you buy AC flush, it is a pressurized bottle you attach to the system to flush out debris. In your case you will remove the compressor, the condenser and the lines. Then flush the evaporator core in the reverse of system operation. Then each line. You may want to replace the accumulator/dryer as well. Then flush the disconnected lines. Replace all the o-rings and reassemble the system. Then vacuum it and charge it.

There are no DIY methods for pulling the vacuum, that takes a pump that can pull a true vacuum. You can sometimes get the pump and gauges as loaner tools but they may ask you for a 609 card these days. That is the certification for working on mobile AC systems. A

Another option would be to do the flush and parts replacement, then take it to a shop for the vac/recharge. Just be sure to tell them what you did repair wise.