Originally the Sabath began sundown FRIDAYs' and ended sundown SATURDAYs'.
Christians live all over the world. In America Christians are free to worship when ever and where ever they want. In some other countries they are not allowed to worship in public, but there are still Christians all over the world.
Because the Christians would not partake of Emperor worship and because they were somewhat secretive in their worship, believers received the wrathful displeasure of some of the Roman Emperors.
Because they did not worship gods or goddesses like the Romans did. Some Christians turned away from their responsibilities as Roman citizens, such as serving in the army.
Christians don't worship places like cities, buildings, altars, temples etc. They worship God and Jesus. If you are asking what are some places where Christians worship, the answer is: everywhere. Whether individually or in a small group or in a large group, Christians worship everywhere. They worship in their homes, in church buildings, in parking lots, in airports, in barns, on the street, in their car, on the train, in school, during work, in a store, in prisons and in any other place you can think of.
Some see it as promoting unchristian principles, such as devil worship. Most Christians simply ignore that aspect of it and have fun.
Some people see us as a regular church. But, we only worship on Saturdays. Some see us as cults (I do not know why).
Where you worship depends on your religion, not your nationality. Most Christians (in Sweden and worldwide) worship in churches, however some prefer to worship at home. Most Jews (in Sweden and worldwide) worship in a synogogue or temple.
Perhaps the most important thing that Constantine did for Christians was to declare religious tolerance, thus allowing Christians (and others) to worship openly. He also gave the main Christian Church of his time state patronage, making it socially and politically desirable for some, to become Christians. He convened and chaired the Christian Council of Nicaea in 325.
Christians do not require any "equipment" when praying. However, some Catholic Christians use the rosary. Both Catholic and Orthodox Christians are more likely than Protestants to use visual representations of Jesus and the saints in their worship, although Protestants often have an (empty) cross in their places of worship as a symbol of Jesus' death and resurrection.
Whether you accept that you can worship Jesus depends on your religious beliefs. Only those who accept that Jesus is God, as Christians do, will feel that they can worship Jesus. What some might find confusing is that we do not worship Jesus by going to a specific place, or performing specific rituals. The worship the Jesus commands is enacted internally and expressed externally - so someone who wishes to worship Jesus will serve fellow Christians and non-Christians. The nature of this service may differ, but ultimately a person doing good deeds to honour God and Jesus is worshipping Jesus by doing that.
Some people do not believe the Bible, but Christians believe it is right.
Pagan Romans believed that there were many gods, and wanted the Christians to worship or at least recognize Roman gods in their worship as well as the Christian God. The Christians wouldn't do this, because it went against their religion to worship more than one god. The pagans also wanted the Christians to do ritualistic sacrifices to their gods, which the Christians also refused to do, as well as worship the Roman emperor. Not worshipping the Roman gods, not sacrificing to the gods, and not worshipping the emperor were all crimes of law in Rome, and so many Christians were killed for not doing these things. Christians were also accused of cannibalism (this is my body, eat this is remembrance of me...), and not contributing to society/laziness.