Basic Understanding of Parallel Tasks with Bonita BPM 6.3.1

First of all I'd like to apologize, because the question may be too basic.
I'm messing with BPM for learning porpuses.

I have created a simple process diagram which include AND-gateways.
The diagram includes several human tasks that can be performed only by some actors in both branches and also following the joint gateway.

Bursaspor – Fenerbahçe Maçi Canli Izle 28 Nisan 2015

Bursaspor Fenerbahçe Maçı Saat Kaçta Hangi Kanaldan Yayınalanacak? - ZTK 28 NisanFenerbahçe Bursaspor maçı ne zaman saat kaçta? Fenerbahçe Bursaspor maçı bu akşam ...Bursaspor—Fenerbahçe — canlı izle:

Modelling Problem with Process Diagram

It may be silly for some but I am having a lot of trouble modelling with what i think is not a complex diagram. Please help me model this, a simple drawing would help

Start task by user Then Task 1 and Task2 are available for some to do them, After Task 1 is completed I need to send a mail and in case of error sending the mail i need to retry every 6 hours. Task3 requires Task1 and Task2 done.

Other Specifications: I do not know if Task1 runs before than Task2 so i think it can't be made by throwing signals or events...