As an administrator, you can grant access to a property by going to the property of interest and clicking on “Property Access” icon - the 3rd icon on the right side of this page.
In the pop-up window you can choose to grant access to a staff member from your staff list, a group, contacts or a guest by using their email address.
When added, select the role of the user (based on your Role templates) and if necessary, set up access expiration time. This is especially relevant for a guest user. As soon as access time expires the user will no longer have access to the shared property.
To further edit User Permissions, click on the user icon under "Permissions" column and check all the permissions that apply. When done click on close button.