Strib, May 25, 2018 (seat becomes open).
Wikipedia, current as of date of this post.
St. Cloud Times, Sept. 16.
DLCC, current as of date of this post.
Perske campaign site:
https://www.perskeforsenate.com/
From there readers can link to an "about" page, a "values" page, and this "donate" page:
https://www.perskeforsenate.com/donate.html
That page presents online donation, and gives mailing info for sending a check.
The Perske home page has a "Get Active" submission form for residents in SD 13 to complete. Out of district contributors would use the "donate" page. With only that Senate District contested along with all the House districts in this election cycle, Perske will be facing a strongly financed challenge.
UPDATE: With the Chinese trade war retaliation tariffs there may be an impact within the district. Readers in the district or knowing people there might want to ask whether trade issues might be expected to be an election factor, or not. Status of the tariff contest by election day could change. Early voting began yesterday. If candidate forum or debate plans exist the Perske campaign should be able to provide information. The St. Cloud Times appears to have not endorsed early. Whether there now exists publicly available early polling is not known here.