overtrue已制作好的伴奏谱如何再加入歌唱声部？

已经制作好的钢琴伴奏谱，想要加入歌唱声部，应该怎么加？

把伴奏导出音频 在多轨录音软件录制
overtrue
自身是无法创建音频轨的

the summer vacation is over. it's true that time always flies fast. during the vacation, the weather was hot and i could not do much work, but i lived happily. 暑假已经结束了。的确，时间总是飞逝如电。休假期间，天气炎热，我不能做很多工作，但我生活幸福。 　as the afternoon was hot,i did my work in the morning.i used to get up at 6: 30 and take a walk in the garden for half an hour. after breakfast,i began reading english and chinese and did some exercises in maths. those took me three hours or more. 1 worked quite hard and made good progress. 由于下午是热，我做我的工作在上午。我通常在6点30分起床，并采取了在花园里散步半小时。早餐后，我开始读英文和中文，并做了一些练习数学。这些我花了3小时以上。我的工作非常卖力，并取得了很大进展。 　i spent the afternoon outside. 1 went to swim and it was funny. i would not go home until it was about five or six o'clock. sometimes a friend would come to see me and we would spend some hours listening to music. 我花了下午外面。我去游泳，这是有趣的。我不想回家，直到五，六点钟。有时候，我的一个朋友要来见我，我们会花几个小时听音乐。 in this way l spent my vacation happily. and i not only studied well but also became a good swimmer. now i am in good health and high spirits. 这样我度过我的假期快乐。我不仅学习不错，但也成为一个很好的游泳运动员。现在我身体健康，保持昂扬的精神状态。