We found the BEST thing was worksheets. The kids had never used them before & we just prepared a double sided, hand written worksheet for each 1 hour lesson and that filled in the time. Seriously, one lesson we didn’t bring a work sheet and the kids were begging for one- they loved it!
In the last 15min or so of each class some kids (usually the girls) would finish their sheet and the slow kids would be struggling so we bought a few packets of pencils and the girls would colour their worksheets and we’d sit down with the boys and make them finish. This worked every time.