Bismillah
Assalamu aleikum
The answer where to put our hands in prayer and about having pictures or statues in the house, is found in Ahadith.
For now I found these two, from Sunan Abu Dawud
Book 3, Number 0754:
Narrated Abdullah ibn Mas'ud:
AbuUthman an-Nahdi said: When Ibn Mas'ud prayed he placed his left hand on the right. The Prophet (peace_be_upon_him) saw him and placed his right hand on his left one.
and
Book 3, Number 0758:
Narrated Tawus:
The Apostle of Allah (peace_be_upon_him) used to place his right hand on his left hand
, then he folded them strictly on his chest in prayer.
About pictures and statues,
Ahadith from Sahih Muslim,
Book 024, Number 5246:
A'isha reported that Gabriel (peace be upon him) made a promise with Allah's Messenger (may peace be upon him) to come at a definite hour; that hour came but he did not visit him. And there was in his hand (in the hand of Allah's Apostle) a staff. He threw it from his hand and said: Never has Allah or His messengers (angels) ever broken their promise. Then he cast a glance (and by chance) found a puppy under his cot and said: 'A'isha, when did this dog enter here? She said: BY Allah, I don't know He then commanded and it was turned out. Then Gabriel came and Allah's Messenger (may peace be upon him) said to him: You promised me and I waited for you. but you did not come, whereupon he said: It was the dog in your house which prevented me (to come), for we (angels) do not enter a house in which there is a dog or a picture.
and
Book 024, Number 5250:
Abu Talha reported: I heard Allah's Messenger (may peace be upon him) as saying: Angels do not enter the house in which there is a dog or a statue.
Wasalam