Gareth Southgate says he has to be realistic when managing the squad's younger players such as Jadon Sancho and Jack Grealish.
Borussia Dortmund forward Sancho has yet to feature in either of England's opening two group games and did not make the bench for the opener against Croatia.
Grealish was handed his first minutes off the bench in England's goalless draw with Scotland, but Southgate said he does not want to rush his younger players into high pressure situations.
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"We've got some explosive options and a lot of them are young players and experiencing a big tournament for the first time," he said.
"So as a coaching staff we are realistic about our expectations of them as individuals.
"Jadon is in that mix. He's trained well the last few days and of course we have got those options and those decisions to make.
"I think a lot of those players we didn't have for the friendlies, so the chemistry is something we didn't have a lot of opportunity to work on.
"We've got to just keep working on that. We know there are some very good players in there, we know they can perform better than they did (against Scotland) and we've got to help them to find that level.
"The important thing is that everyone gets behind the team and the players and they're going to need to feel that support and to feel that warmth.
This is a relatively inexperienced group, I think the third least caps in the tournament. Against Scotland, it was a young team so that's a different experience for a lot of them than they've ever faced before
"They've just about survived it. We want to be better and that's what we're going to work through in the next few days before we play the Czech Republic."
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