There are two ways you can assign users access in Calira. The first is on an individual basis, which is the way you are describing. The second is via an access group.
An access group lets you create a group of users and then assign equipment and rules to the entire group at once. To create an access group, head to the users page and then select the Access Groups tab. You will notice a default group called General on there already, this will have all your lab users assigned to the group but no equipment assigned to it. You can either edit this group or create a new one, and assign all the equipment you want people to have instant access to.
Please note - users cannot have access to the same instrument via their individual rules and an access group at the same time. If you are trying to add all equipment in your lab to all the users in one group, you will likely need to go back through the individual user settings you have assigned equipment to and unassign them before you can add them to the group.
To automatically add a user to this access group when they join the lab, and therefore give them instant access to the equipment assigned to this group, when you are sending the invite to the user you can press Advanced Options and then select which group they should be added to when they accept the invitation.