McEwan, into his third week at the helm of the Stags, also called for fans to be patient, after the 1-0 win at Hucknall Town.
The Stags, including 10 trialists among 20 players who featured in the 90 minutes, have yet to boost their first team squad to 11 players.
- Meet the 10 trialists, match report and match photos
But McEwan promised fans that he would not sign players for the sake of bolstering his squad.
He said after Michael Blackwood, one of his four signings so far, had struck the only goal of the game: "I just ask that the fans are patient. Rome was not built in a day. We have got to have patience as a group and as fans."
McEwan said that he was aiming for a squad of at least 20 players by the start of the season, but warned that some may be at Field Mill on short-term contracts or a non-contract basis while he made a final decision about their futures.
"I could fill the club with 30 to 40 players and it is easy to sign players, but I have got to make sure that they are the right ones for this club."
On a personal note back in charge of a team in a competitive match for the first time since his departure from York, he added: "It is good to be back, you do miss it. I have been in the game for 40 years, it is in my blood, it is like a drug.
"You need a challenge and this is a challenge. But look at this club as a whole . . . things are changing for the better, the facilities off the pitch are improving, the business side is improving already.
"The fans have been excellent. I have been in seven days a week and spoken to some. They are optimistic about where the club is going to go, but it will take time. This will be a smashing club, but we are at rock bottom now.
"When I came we have just two contracted senior players, Nathan Arnold and Jason White. This is a McAlpine job, a massive rebuilding job.
"But I have to be careful we get the right players in as pennies are tight. I have been doing my homework on these players, they don't just arrive on your doorstep willy-nilly.
"We need players with the right character who want to come and play for us."
And midfielder Jon D'Laryea - one of McEwan's four signings so far after being released at the end of last season - was full of praise for his teammates after the win.He said: "Michael (Blackwood) looked sharp, direct and willing to take players on. He chipped in with a goal and showed fans he could be exciting.
"Adie Moses and Paul Hurst used their experience well. Adie is solid and not a lot gets passed him.
"Most of the lads can be happy with their performance.
"Now we need to make sure we don't take a step back, that we keep improving."
On veteran striker Mark Stallard, he added: "He can help all the lads. He will be an inspiration to the younger strikers and is a great asset to the squad."
The full article contains 577 words and appears in n/a newspaper.