My answer will assume you can work in air and shift the bacteria to low oxygen. If they are very sensitive you will need an anaerobic hood. So start with plating your bacteria in room atmosphere.

Depending on how oxygen sensitive they are you can

1. Use the "candle jar" see Fig 15 in https://www.jfmed.uniba.sk/fileadmin/jlf/Pracoviska/ustav-mikrobiologie-a-imunologie/ANAEROBIC_BACTERIA.pdf. This will reduce oxygen to 8-10% (as compared to ~20%)

2. Place the plate/tube in the desiccator, pump out some air (don't over pump), fill with nitrogen from cylinder, pump, fill, etc until you think you are good. If you have a vacuum/pressure gauge you can estimate the leftover oxygen concentration by calculating the dilution.

3. Buy an anaerobic jar and bag... Probably the easiest and will be cheaper then (2).

4. Poor man solution - place your petri dish in mylar bags such as used for food/electronics and either throw in an anaerobic packs or fill the bag with N2 or gas mixture. Soldier the bag with food vacuum sealer.

An adaptation of (4) I did not try - use vacuum bags used to reduce the size of packages at home, pump, add N2, pump, etc. The benefit - much less N2 is needed.

Thanks so much sir for your answer