If you are working with collaborators to do your cryopreservation, you need to be in touch with them on how they want to receive your material. If you will be doing the cryopreservation yourself, your next step is to test how your plants react to cryoprotectants.
Sometimes pre-cryo treatments can be used to help increase survival through cryo, such as cold treatments or growth on media with increased sugars, etc. The treatment, or whether you need one at all, will depend on the species. The shoot tips will also need to be dissected. Since shoot tips of different species can have different morphologies, excising some and trying to regrow them will provide a first indication of their ability to go through the cryo process. This would be an “isolation control.” This can also help refine the recovery medium, if needed. Once there is success with the isolation control, a preculture medium can be tested, followed by testing with the cryoprotectants that will be used.