Tietjens' side will take on defending series champions Fiji and Wales and Canada in pool play.
Fiji lost to South Africa in the Dubai sevens semi-finals last week while Wales and Canada had disappointing tournaments.
Samoa finished in sixth place and look to have made improvements from last season.
But Tietjens said he expects their group to provide stiff opposition.
"Canada is going to to be really tough, they are disappointed with their last tournament. Obviously they will want to get a few points on the board."