I recently became AS (Autonomus System).
As from the beginning I have configured an eBGP Router that announces my Public / 29 network.
Is your ASN a private one for routing between you and the ISP or are you intending to announce into the global routing table? If the later, it will only work with a minimum of /24 of IPv4 or /48 of IPv6. Any smaller then this and a large percentage of the internet (including us) will filter your routes out.
Both allow me to get the FIRT (Full Internet Routing Table) but I have no idea how to set up a backup eBGP session in case my primary ISP is down.
EBGP is intended to be always on - not active / fail over.
You are advised to get full tables to obtain the most benefit from diverse uplines. Make sure your router can handle this - ie: CCR1009 or better. The CCR2004 is a good choice.
Unless you have a specific reason for preferring one ISP I would treat them both equally and let the traffic fall where it may. Do be aware you can really only control your ongoing traffic. You could try and engineer incoming through AS-prepend but this only has limited effect. Also be aware no matter what you do - upline ISP's and their uplines will always prefer to send you the traffic through a client of theirs (local pref) regardless of anything else.