Follow the spam guide for the event - Just keep spamming the first/2nd mission (there is exact amount of tickets written on the previous pages) and even with new weak team you can easily get the 2K needed for a fully upgraded 5* that will help you in the future events.
Two events like this, after each other, are very good for new players, as it allows them to get some solid 5* units without the need to have a strong team. All that is required is patience to grind away at the event and at the end you get units that once leveled up will help you a lot in the future. Good for you guys, keep at it and bash out those tickets