Doninia,
you may want to have a look into
ISO 10993-1:2018, Fig 1, which provides you with a flowchart that walks you through the evaluation process. Section B.2.2 tells you a little bit about the evaluation plan.
A word of caution: without previous exposure to / experience in biocompatibility evaluations, you may want to to seek professional support (also in line with ISO 10993-1:2018, section 4.1 - quote "the biological evaluation shall be planned, carried out, and documented by knowledgeable and experienced professionals.")
HTH,