Can you provide some details about your setup? For example, what type of AC transformer do you have? Are you using a WiFi dongle or wired Ethernet connection? Have you set up a sprinkler program and if so does it open multiple valves at the same time?
One likely cause for the rebooting is that the voltage may be dropping below an acceptable level. For example, if the AC transformer’s current rating is not sufficient, or if multiple valves open at the same time that exceeds the capability of the transformer, or if for some reason the RPi is drawing a large amount of current from OSPi. Knowing your setup will help diagnose the cause.
Regarding the screws and support pillars, sorry about that. Those should be included in the kit in a blue plastic bag. You can send an email to [email protected] with your address and we will send it to you. Thanks.