To send bulk emails,
Go to the Leads tab if your recipients are leads, else click the Contacts tab.
Select a view or use filters to get a refined list of leads/contacts.
You can handpick individual leads/contacts by selecting the checkbox beside their names, or you can just click the checkbox beside NAME to select all the records from a view.
On selecting the recipients, the bulk actions tray appears. Click the Bulk email icon.
Compose your email in the overlay. You can use placeholders to personalize your emails, or you can just select a template from the drop-down.
Up to 25 additional records can be added from the bulk email overlay section even after selecting multiple leads or contacts from the list view.