Next is apply to SINP with all the required documents within 60 days of the invitation.
https://www.saskatchewan.ca/residents/moving-to-saskatchewan/live-in-saskatchewan/by-immigrating/saskatchewan-immigrant-nominee-program/browse-sinp-programs/applicants-international-skilled-workers/international-skilled-worker-saskatchewan-express-entry
If it's a different stream then follow:
https://www.saskatchewan.ca/residents/moving-to-saskatchewan/live-in-saskatchewan/by-immigrating/saskatchewan-immigrant-nominee-program