'Convert' Button

I have set up a number of leads and would like to be able to turn these into contacts and/or accounts. When I follow the instructions here https://help.zoho.com/portal/en/kb/crm/sales-force-automation/leads/articles/convert-leads#Creation_of_contacts_and_accounts_upon_lead_conversion

the instructions say:

Click the Leads tab.
In the Leads Home page, select the lead to be converted.
In the Lead Details page, click Convert.

(attached screenshot Zoho_1). However, I do not have a 'Convert' button top right (attached screenshot Zoho_2). Should this appear automatically, or how do I set this up?