In Sendlane, go to Campaigns, then click New Campaign

In Create New Campaign modal, press Create SMS Campaign

Name your new campaign, then at Audience/Send to, make sure you select the newly created segment HiTide,

Then add a Text Message and press Next to Summary

Select Send Immediately and press Send Immediately button. Also if you dont want to send the campaign Immediately you have the option to Save as Draft or Schedule the campaign