multiple remote data sources - guidance

Hi I work for a trust of 10 school. The school are not linked by domain or connection at all.

Each school runs the same management information system.

I have a power bi account in the trusts tenancy. The MIS at each academy will run the exact same reports so the data extract will be the same.

How do i get all 10 schools data to the trusts power bi so I can make a report?

I have read through the on-premise data gateway stuff. My understanding so far is I install this on each location the data files will be stored and link them to my trust power bi account. So my Gateway setting would then show 10 locations in the gateway cluster.

So if the gateways are linked successfully how do i then form a datset using the gateway data? The only options i get are onedrive, local or sql.

I haven't started this part of the project yet i'm trying to plan ahead. Am I using the right method? will it make sense as I go forward?