How do I link with our PayPal account

We are using this as a membership registration and will have another form for a conference registration.  Not sure how I link this with our OBEA PayPal account.

Also, some people may not want to use PayPal, and would rather write a check.  How do they "SUBMIT"  their registration information without paying through PayPal

You can integrate paypal with using the available widgets,

Use this detailed guide on how to do paypal integration with your form : Paypal Integration

Regarding your second inquiry about alternative payment method with paypal, you can use form conditions to switch between payment options here is  a guide that will give you detailed information on how to achieve this

http://www.jotform.com/help/120-How-to-set-up-paypal-along-with-other-payment-options

Please let us know if further assistance is required.