It’s normally quite easy to find novena prayers - often those holy cards of different saints will have a novena on the back, or there are books which contain several different novenas. Normally there is a formula which can differ from novena to novena - a prayer petitioning the particular saint in whose honour you offer the novena, one mentions their request, and then something like an Our Father, Hail Mary and a Glory Be… as I said it varies, but any I’ve come across have had the same basic outline and were easy to follow. There is also the option of making a Novena of Masses for your intention.
I believe that all prayer is powerful, and if a prayer is offered with faith and sincerity you may be sure that God will help. It is said that God has three answers to prayer: “yes”, “not now”, or “I’ve something better in store for you”. So, make your novenas - it’s just one of a range of prayer methods - but above all, have faith that God knows whats best for you and be prepared to accept His will, even if it appears that He is saying “no”.