Rent Single Unit:

 From the WordPress dashboard click on 6storage -> Settings. 

After selecting the Settings you will land on the tenant portal setting page.

To customize for your business requirements, click on Feature customization you will find Fields, Additional addons & other operations.

Disable:

By disabling the Rent single unit, you will have an option to choose multiple units with multiple sizes only for the “Rent now” option.

Tenant portal:

On the tenant portal, you can see the option available to rent multiple units.

Step 1:
You can select multiple units of different sizes or you can as well rent a single unit

Step 2:
 After selecting the units click on the rent now button which is on top to rent those units. 

Enable:

By enabling the Rent single unit,  the option to choose multiple units with multiple sizes will not be available.

Tenant portal: