Hi,
I am using Salesforce Lightning. I need to create a 'Log a Meeting' button, exactly like 'Log a Call'.

I have gone through the forums and found how to create the button in Salesforce Classic mode - following the below
Firstly, create this new custom button.
1. Navigate to Setup > App Setup > Customise > Activities > Event Buttons and Links
2. Click New
3. Type under Label 'Log a Meeting'
4. Tab once at you will see 'Log_a_Meeting' is populated under Name field
5. Leave the behaviour as 'Display in existing window with sidebar'
6. Leave the Content Source as 'URL'
7. Enter in the blank space the following:
/00T/e?who_id={!Contact.Id}&followup=1&tsk5=Meeting:Enter Activity Subject Here&retURL=%2F{!Contact.Id}
8. Click Save.

Then I added it to the page layout
Setup > App Setup > Customize > Accounts > Page Layout > Edit > Go to related list > Properties of  Related list > Buttons >

The button works - but only when in Salesforce Classic. When I swap back to lightening, I can't see it.

How do I see it in Salesforce Lightening?