Shelly, alarms, and a beginner

aged beginner here, working my way through my Home Assistant installation. Have a few basic things working (light switches, and automations) and want to tackle an alarm system using Shelly devices. I have some basic questions to which I could not readily find answers…

Q1 - Do I need to install the Shelly integration in order to use any Shelly device ? I have a couple of Shelly buttons I want to use to run some scenes, and also hope to use Shelly motion sensors and door-window sensors to set up al alarm.

Q2 - What is the best alarm set-up using Shelly sensors ? Alarmo ? or the HA Manual Alarm Control Panel ? something else ?

Any pointers on this anyone may have for a retired fellow new to HA woudl be most welcome !

Q1, yes that is the easiest way. Read the documentation, particularly: https://www.home-assistant.io/integrations/shelly/#known-issues-and-limitations

Q2, yes Alarmo makes it very easy to set up an alarm system and works flawlessly.

Many thanks for the pointers ! I’ll read some more… and give it a go. Cheers!