Many-to-many Relationship

I’m building a database of protein mutants we use in the lab. A lot of analysis is done on these proteins by various people and it’s becoming a bit of a nightmare keeping track of all the information per protein. What we need is a database. I’m getting a reasonable grip on it all I think with the excellent examples I have found on the forum but there are obviously areas that I have great difficulty with. The main problem for now is that many-to-many relationships are involved and I just cannot get them to work properly.

On each protein up to 8 different types of test are performed. To keep things easy I’ll call them A1 (for Analysis1), A2, A3 etc. These are done by different people from a group of 7. I’ve called them O1 (Operator1), O2, O3 etc. Each of the operators can do multiple analysis and the operators overlap. So e.g. O1 might be particularly good at A1, A4 and A7, O2 might be good at A2, A4 and A5, and O3 predominantly does A1, A4 and A6. What it comes down to is that each operator can in principle do each of the analysis so I have to give that option in the database.
What does work (but is not the solution as it introduces 8x duplication of data) is if I have a separate table with operators for each analysis. The same tblOperators is linked 8 times. There must be a way to link each of the analyis to only 1 tblOperators, probably with the use of a linking but I just cannot work it out from the examples I've found here.

Can someone help me on my way please?

Thanks,
Walter