I would like to be able to create a path for my tasks. I have seen that activities can be used as such. Indeed when one is done, it can trigger a new task to be created and assigned. However, it does not seem to work as such with task. Furthermore, it does not seem to be possible to have the input of a customer or a lead being the event triggering the next task to be created. For example, the task could be to get a meeting with a customer, once it is done, the next step is writing a quotation. Knowing this, do we always have to set them up manually? 
Another question is the use of mails in the app. It does not seem easy to send mails from the project nor the CRM app. Could you enlighten me on this?

Thanks in advance!