Dear Lords of the Codes!

I'm new to coding and metagenomic analysis. Could anyone help guide me through the process of solving this problem that I have ? I have a genus of cyanobacteria that I have 16S data for (about 1.7 kb which covers nearly all of the 16S), and there are multiple species in this data set. I want to scan for 16S with high similarity (> 98%) across all microbiomes, and report the abundances of these sequences if possible. I suspect that this genus prevails in desert soil, and are rare or absent in other microbiomes. If there are necessary steps to clean the data before processing, please educate me!

Thank you so much!