Open Slack and sign in to your workspace
Click the workspace name in the top-left corner
Select Create a channel
Enter a channel name
Choose whether the channel will be public or private
Click Create
Open the new channel
Click the channel name at the top
Select Add people or Invite people
Enter the names or email addresses of the members you want to add
Select the users from the list
Click Add or Invite
Repeat as needed to invite more members